Thermal responsive device



Sept. 17, 1957 c. w.=woo|:

THERMAL RESPONSIVE DEVICE Filed Jan. 28. 1955 INVENTOR. C HAR l. Es vvfTOFmEY United States Patent THERMAL RESPONSIVE DEVICE Charles W. Wood,Lebanon, Ohio, assignor to Standard Thomson Corporation, Dayton, Ohio, acorporation of Delaware Application January 28, 1953, Serial No. 333,7074 Claims. (Cl. 73--368.3)

responsive device which has long life, and dependability;`

one which is easily produced and is inexpensive to construct.

Another object of this invention is to provide a thermal responsivedevice which is adaptable for use as a thermostatic control device orfor use as a temperature ndicatng device.

Other objects and advantages reside in the construction of parts, thecombination thereof and the mode of operation, as will become moreapparent from the following description.

Referring to the drawing,

Figure l is a side elevational view of an `embodiment of the thermalresponsive device under normal temper-A atures, with a portion of thedevice shown in section.

Figure 2 is a side elevational view, with a portion in section, of thepreferred modification of the thermal device during temperatures higherthan normal.

Figure 3 is a top sectional view of the device, taken substantially online 3 3 of Figure 1.

Figure 4 is a perspective view of the spool portion of the device.

Figure 5 is a side sectional view of another modification of the thermalresponsive device.

In the drawing, the reference numerals and 12 indicate two end plates ofthe thermal device, as clearly shown in Figures l, 2, and 3. These endplates are retained in position by bolts 14 and nuts 16. Each of the endplates 10 and 12 is provided with a centrally located orifice. Theorifice in end plate 10 is larger than the orifice in end plate 12. Theinner surface of each end plate is provided with an annular groove. Acylinder 20 has radially disposed flange portion 18 at each end thereofterminating in annular rings 19 which are positioned in the annulargrooves of the end plates 10 and 12.

A spool 22 is firmly positioned within the cylinder 20. The spool 22 iscomposed of elastic material, such as rubber, or synthetic materialshaving the qualities of being substantially incompressible, but elastic,permitting ow of the material. Flat portions or annular flanges 24 ofthe spool 22 are firmly retained in and by the ends 18 of the cylinder2i), as the flat portions 24 abut the inner surface of the end plates 10and 12. As clearly shown in Figures l and 2, each of the ends of themain body portion of the cylinder 20 terminates in a rib portion 21,clamping the fiat portions 24 against the end plates 10 and 12.

A longitudinal hole 28 through the center of the spool 22 extends aportion of the length of the spool at one diameter and tapers down to asmaller diameter for the remainder of the length of the spool. Anactuator 30, shown in Figure l, consists of a pin having two cylindricalportions, a larger diameter portion 32 and a smaller diameter portion 34joined by a frustum-conical shoulder portion 36. p

The embodiments of the invention shown in Figures l and 2 aresubstantially the same, excepting that the actuator memberll disclosedin Figure l is different from an actuator 37 disclosed in Figure 2. Theactuator 37 is a hollow cylindrical member having a tapered end and acentrally located hole throughout its length. A guide pin 38 is firmlyattached t-o a lower end plate 40. The guide pin 38 extends through thecylinder 20 and through the orifice in the end plate 10. The actuator 37slidably lits over the pin 38 and is adapted to move along the pin3S,while moving through the orilice provided in the end plate 10. Theactuator 37 of Figure 2 and the actuator 30 of Figure l are adapted tofit snugly within the/hole 28 in the spool 22.

The space between the spool 22 and the Walls of the cylinder 20 forms anannular compartment which is occupied by an expansive material 39. Thisexpansive material may be any element or any combination of elementsgiving the material the physical property characteristic of a highcoefiicient of expansion over a given temperature range. A material isselected to provide the desired expansion and flow characteristics overthe desired temperature range for a given application.

As the temperature of the thermal device increases above normal, theinitial expansion of the expansive material is small. However, as thetemperature continues to rise, a temperature point is reached at whichthe amount of expansion per degree of temperature change greatlyincreases. Decrease in temperature results in contraction of thematerial.

The volumetric expansion of the expansive material 39 results inexertion of pressure upon the spool 22. The pressure upon the spool 22forces the elastic material of the body of the spool 22 to move inwardly(as shown in Figure 2), tending to close the hole through the spool. Dueto the fact that the elastic material of the spool 22 is incompressible,the radial, inward movement of the elastic material results in movementof the actuator, as shown by dotted lines in Figure l. The actuatormoves in a direction out of the cylinder Ztl. The actuator 30 of Figurel is guided in its outward movement by the end plates 10 and 12. This isdue to the fact that the two cylindrical portions 32 and 34 slidably fitin the orices of the end plates lil and 12. The amount of outwardmovement ofthe actuator is, of course, dependent upon the amount ofexpansion of the expansive material 39.

An actuator may be employed to operate a control device, or the actuatormay be connected to an indicating device for indicating temperature.This thermal responsive device may also be employed in a dual purpose ofindicating temperature while controlling temperature.

A modiication of the thermal responsive device is disclosed in Figure 5.A cup 50 retains a cylindrical elastic spool 52, having a disc type head53. The head portion 53 of the elastic spool is fastened., as by a rib55, within the cup 50 near the top thereof. The lower part of the bodyportion is retained by rib 57. Surrounding the body of the elastic spool52 is the expansive ma terial 39. A plate 54, having a centrally locatedorifice therein provides a cover for the cup and aids in fastening thehead portion 53 of the elastic spool 52 to the cup 50. The upper edgesof the cup Sil are turned down upon the plate 54.

The elastic spool S2 is provided with a centrally located cavityextending a portion of the distance through the Y 3 elastic spool 52. Anactuator 56 is adapted to slidably t within the cavity of the elasticspool 52. The movement of the actuator 56 is similar to the movement ofactuators 30 and 37. As the temperature of the expansive material 39increases, the volumetric expansion of the expansive material Vforces,movement inwardly .of the sides of the body o'f the-elastic spool 52,thus tending to close the internal cavity. This inward radial movementforces the actuator in a direction out of the cup 50.

'This thermal responsive device may be used ias a thermostatic controldevice or ,as a temperatureindica-ting device.

Although the preferred embodiment of the device has been described, itwill be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts, the combination thereof and mode `of operation, which generallystated consist in a device capable of .carrying out the objects setforth, as disclosed and dened in the appended claims.

Having thus described my invention, I claim:

1. In a thermal responsive device, the combination -including acontainer, a spool comprising an elastic material retained within thecontainer, the spool having a body portion, the body portion engagingopposite end Walls of the container, the body portion being providedwith wall members forming a centrally located longitudinal hole thereinopen at one end thereof and extending a portion of the length thereof,the remainder of the body portion being solid, said remainder of vthebody portion having a greater length than the thickness of the wallmembers, an actuator snugly positioned within the hole in the bodyportion of the spool, an expansive material within the containersurround-ing the body portion of the spool so that as the expansivematerial expands with increased temperatures thereof such force isexerted upon the body .portion of the spool that the elastic -materialforming the wall members in the body portion moves inwardly tending toclose the hole in the body portion of the spool, the closing action thuscausing Lan extrusion action forcing longitudinal movement of theactuator in a direction from the spool.

2. In a thermal device comprising a cup shape containerj a cover memberhaving an aperture therein closing the cup shape container, acylindrical elastic spool within the container, each end of the spoolbeing in engagement with internal wall surfaces of the container, thespool being provided with a longitudinal centrally located hole thereinextending through only a portion of the spool and concentric with theaperture in the coverV 4 r thereof, the remainder portion of the elasticbody being solid, a cylindrical actuator rod snugly tting within thecavity and slidably extending from the container through one of saidenclosing walls thereof, the thickness of the wall members forming thecavity being less than the length of said remainder portion of theelastic body, an expansive material filling the space between theelastic body and the container, the expansive material being such amaterial that -its -v-olume changes with variations in temperature thusproviding means whereby the elastic body is deformed, `said wall membersforming the cavity in the elastic body being forced inwardly tow-ardY,the longitudinal axis of the body upon expansion of the expansivematerial, which movement of the -wall portions causes an extrusionprocess and forces movement of the actuator in a direction from theelastic body, the amount of movement of the wall portions beingdependent upon the temperature of the expansive material, both of thelongitudinal ends of the elastic body `being in .engagement with saidopposite enclosing walls of ,the Container during expansion of theexpansive material.

4. In a thermal responsive device, the combination including acontainer, an elongate elastic body retained within the container andhaving ylongitudinal end surfaces in engagement with opposite end wallsthereof, the elastic body having wall members extending a portion of thelength thereof forming .a centrally located longitudinalcavity therein,the cavity'being .open at one end .thereof and extending a portion ofthe length -of the elastic body, the remainder portion of the length ofthe elastic body being greater than the thickness of the -wall membersforming the cavity in the elastic body, an actuator rod snugly4positioned within the cavity in the elastic body, the actuator rodextending from the elastic body and through one of said end walls of thecontainer,an expansive material within `t-he ycontainer encircling theelastic Abody so that ,as the expansive material expands with increasedtemperatures thereof the expansive maf terial exerts forces upon theelastic body so that the wall members forming the cavity move inwardlytending to close the cavity, the closing movement -of the Wall membersthus causing extrusion of the actuator rod forcing axial movement of theactuator rod in a direction from the elastic bod-y, said longitudinalend surfaces ofthe elastic body being in engagement with said oppositeend walls of the container during expansion of the expansive material.

References Cited in the tile of this patent UNITED STATES PATENTS2,076,406 Kern Apr. 6, 1937 2,208,149 Vernet July 16, 1940 2,241,086Gould May 6, 1941 2,355,043 Adlam Aug. 8, 11944 2,453,851 Miller Nov. 161948 2,507,466 De Craene May 9, 1950 FOREIGN -PATENTS 436,836 GreatBritain lOct. 18. 1935

